/**
 * 枚举
 * 为了描述一些固定的值
 * 枚举成员会被赋值为从 0 开始递增的数字，同时也会对枚举值到枚举名进行反向映射
 */
var Days;
(function (Days) {
    Days[Days["Sun"] = 0] = "Sun";
    Days[Days["Mon"] = 1] = "Mon";
    Days[Days["Tue"] = 2] = "Tue";
    Days[Days["Wed"] = 3] = "Wed";
    Days[Days["Thu"] = 4] = "Thu";
    Days[Days["Fri"] = 5] = "Fri";
    Days[Days["Sat"] = 6] = "Sat";
})(Days || (Days = {}));
;
console.log(Days['Fri']); // true
